Radiotelephones are used in a variety of wireless communication systems all having different air interface requirements. These various air interface systems include cellular radiotelephone systems, cordless telephone systems and other numerous wireless telephone system arrangements including Personal Communication Networks (PCN) and services. All these arrangements require a radiotelephone handset designed to operate in the air interface system unique to that particular communication system. A radiotelephone handset is generally capable of operating in only one environment (i.e. cellular, cordless, etc). Hence to provide ubiquitous services and to operate across systems with varied air interfaces requires a different radiotelephone handset for each system.
Prior approaches to extend the use of a radiotelephone handset into more than one wireless communication system have included the joining of two separate radiotelephone handset units, each one operative in each and only one of the available wireless communication systems, into one unitary package. Only one of these independent units is operative, however, at one time. Operation in the different air interfaces is accomplished by switching from one unit to the other independent unit as desired. Such an arrangement is described in the U.S. Pat. No. 4,989,230 which discloses a cellular cordless telephone in which separate cellular and cordless transceivers are joined together in a single package. Each transceiver is connected to its air interface by way of its own individual antenna.